1. Field
Embodiments of the inventive concept relate to methods of forming a gate structure and methods of manufacturing a semiconductor device including the same. More particularly, embodiments of the inventive concept relate to methods of forming a gate structure including a metal and methods of manufacturing a semiconductor device including the same.
2. Description of the Related Art
To decrease a leakage current through a gate insulating layer of a transistor, a method of forming the gate insulating layer using a material having a high dielectricity has been developed. When a gate electrode including polysilicon is formed on the high dielectric layer, some problems may be encountered including an increase of a threshold voltage of the transistor by a Fermi pinning phenomenon, a decrease of electron mobility, a decrease of a flat band, etc.
Accordingly, a method of forming a gate structure formed by integrating a metal layer and a polysilicon layer on the high dielectric layer one by one may be applied. However, when the polysilicon layer is formed on the metal layer, an oxide layer may be formed at an interface of the polysilicon layer and the metal layer to deteriorate characteristics of the gate structure. Accordingly, a method of forming a gate structure having a good electric property may be desired.